Osteochondromas

Osteochondromas occur underneath the toenail when benign bone tumors form in that area, typically after injury. Most common in children and young adults, osteochondromas account for approximately 50% of all benign bone tumors.
Most of the time, osteochondromas do not cause pain; however, discomfort can result if they irritate surrounding tissue. If osteochondromas deform the toenail or cause it to become ingrown, they can be surgically removed. Osteochondromas can become a recurring condition.